Re: [PATCH]generic usb serial driver
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Organization | Novell |
| Message-ID | <[email protected]> |
Am Samstag, 31. März 2007 04:59 schrieb Alan Stern: > isn't clean -- but several drivers do it this way. I'm not even certain > that adding smp_mb() to the completion routine will really fix it; memory > barriers have to be used in pairs, and so there would also need to be a > barrier between the test of private_data->urb_done and the call to > use(urb). > In the example you have given smp_rmb() would be required. However we have: CPU A CPU B a = urb->status if (flag) flag = 1 urb->status = x abstractly speaking. CPU A needs a memory barrier. Are you saying that CPUs may do speculative _writes_ ? Regards Oliver ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel